The most common cause of male infertility is low sperm count. Absence
of sperm in the semen is less common, affecting 1 out of 100 men and affecting 10 to
15 out of 100 infertile men.1
Causes of sperm count problems include:
- Hormonal problems in the
pituitary gland. The pituitary gland releases hormones
that stimulate the testicles to produce
- Testicular injury or
failure, either present at birth (congenital) or associated with radiation or
toxic chemical exposure.
- Cancer treatment with certain kinds of
chemotherapy or radiation.
- Antibodies that
attack sperm and that also may be present in semen. Sperm antibodies sometimes
develop when a man's sperm has been exposed to his immune system (outside of
the testicles). This may happen after a vasectomy, an infection, or an injury
to the testicles.2
- Drug use (some
prescription medicines, and marijuana and tobacco
- Structural problems. These include:
varicocele in the testicles.
ejaculation due to a surgical
- Absence of a
vas deferens (a birth defect that may be associated
cystic fibrosis genes).
ejaculation (the ejaculation of semen into the bladder rather than out through
- Chromosomal problems (such as
See a picture of the
male reproductive system .
American Society for Reproductive Medicine and Society for Male Reproduction and Urology (2008). Evaluation of the azoospermic male. Fertility and Sterility, 90(Suppl 5): S74–S77.
Fritz MA, Speroff L (2011). Male infertility. In Clinical Gynecologic Endocrinology and Infertility, 8th ed., pp. 1249–1292. Philadelphia: Lippincott Williams and Wilkins.